Abrading apparatus



June 30, 1970 a. E. BALDWIN- ETAI- 7,

ABRADING APPARATUS Filed March 21, 1968 a Sheets- Sheet 1 Fig. I G

1 N VEN '1 URS. BRIAN E. BALDWIN 34 BY HERBERT E.KARL|NSKI PRESSURIZEDAiR ATTORNEY.

June 30, 1970 B. EJ'BALDWIN ETAL 3,517,461

Asxmm AP'PARATUS Filed March 21, 1968 a Sheets-Sheet 2 IN VEN'TOR S.

BRIAN E. BALDWIN HERBERT E.KARLINSKI ATTOR NEY.

United States Patent O 3,517,461 ABRADING APPARATUS Brian E. Baldwin,Wilmette, and Herbert E. Karlinski,

Chicago, 11]., assignors to Pennwalt Corporation, a corporation ofPennsylvania Filed Mar. 21, 1968, Ser. No. 714,945

Int. Cl. B24c 3/00 US. Cl. 51-42 10 Claims ABSTRACT OF THE DISCLOSUREThe abrading apparatus includes a pressure vessel which houses a storagereservoir and a distributor for abrasive material. The vessel has aninlet for pressurized gas and a plurality of outlets for gas-borneabrasive material, the distributor being angularly movable about anupright axis to distribute the abrasive material from ananularly spacedlocations through the outlets and preferably being reciprocated in aninclined arcuate path by a rotary vibrator. Provision is made to signalwhen the pressure vessel is not locked shut and also when the storagereservoir is almost depleted of abrasive material.

This invention relates to abrading apparatus of the type which might beemployed for trimming, cutting, cleaning or deburring articles ofmanufacture.

Apparatus of the type set forth is shown, for example, in US. Pat. No.2,696,049 to Black and also US. Pat. No. 3,344,524, issued Oct. 3, 1967,in the name of Walter Kulischenko and assigned to the assignee of thepresent invention.

One of the limitations of otherwise satisfactory abrading apparatus isthe ability to supply gas-borne abrasive material from a central sourcein uniform concentrations to several nozzles over an extended period oftime. To do this requires apparatus capable of storing a large amount ofabrasive material and of equally distributing the same therefrom in thesame ratio to duplicate gas streams flowing through a number of supplylines, all to the end of continuously achieving like cutting action byall nozzles. This permits a particular abrading operation to be carriedout simultaneosuly at a number of adjacent work station, for example ona number of parallel assembly lines, with uniform results.

Apparatus for carrying out the present invention supplies nozzles withgas-borne abrasive material from a pressure vessel which is fed withpressurized gas and which houses an abrasive distributor and a reservoirfor replenishing the supply of material in the distributor. According tothe present invention, the distributor is angularly movable about anupright axis and is provided with outlets at spaced locations about theaxis through which the abrasive material is distributed. Preferably theoutlets in the distributor are arranged to extend tangentially to theannular wall, the latter being formed about the axis of movement of thedistributor.

It is also preferred that the distributor be moved an gularly by asuitable drive so as to reciprocate, with the distributor lifting androtating the material in one arcuate direction on a distribution strokeand moving in opposite direction to original position on a returnstroke.

Provisions are made for a single to be given when abrasive material inthe storage reservoir is reduced to a low level, also for signallingwhen the separable parts of the pressure vessel are unlocked and forclosing off the pressurized gas supply, for heating the pressurized gassupply, and for keeping the distribution outlets clear of accumulationsof abrasive material.

These and other objects, features and advantages of the invention willappear more fully from the detailed Patented June 30, 1970 descriptionwhich follows, taken in connection with the accompanying drawingsforming a part of the present application and in which:

FIG. 1 is a vertical sectional view of apparatus embodying theinvention, taken along line 1-1 of FIG. 2, and

FIG. 2 is a horizontal sectional view of the same apparatus, taken alongline 22 of FIG. 1.

The abrading apparatus shown in the drawings comprises a pressure vessel10 including a generally fiat base 12 supporting a dome or bell-shapedshell 14 of circular cross section. The latter is provided with alifting ring 16 which may be employed when moving the assembled vessel10 and when separating or reuniting the shell 14 and base 12. Inside thevessel 10, a storage reservoir 18 for abrasive material is supported inelevated position by a stand 20 in position to feed or replenish anabrasive distributor 22 therebelow by gravity as the contents of thedistributor are metered and fed through a funnel entrance 23 of outletlines 24 leading to nozzles. One source nozzle is shown in FIG. 1 anddesignated by the numeral 21. The abrasive material is carried throughthe lines 24 by streams of air or any other desired gas brought into thevesel 10 under pressure via inlet 26 in the base 12. As best seen inFIG. 1 the outlet lines 24 each have a downstream portion comprisingflexible tubes 25 joined to the base 12 by a threaded fitting 27.

The apparatus of the present invention is preferably employed forabrading with alumina or beaded glass powder, although the invention maybe practiced while using any suitable finely divided or particulate hardmaterial. It is recommended, however, that highly hydroscopic materialsbe avoided in order to minimize the plugging of flow passages and theencrusting of component parts. Hygroscopic water can be eliminated bypreheating the abrasive materials to above 212 F., and by delivering adry carrier gas to the vessel 10. Still another consideration iscorrosion; and therefore non-corrosive abrasives are preferred as theworking material and stainless steel is the material of choice for theapparatus, especially for those components contacted directly by theabrasive material.

Briefly stated, the abrading operation is carried out by impinging ahigh velocity stream of airborne or gasborne abrasive particles on thesurface being abraded. Such stream is provided by introducing theabrasive material into the gas stream as it flows through the vessel 10between the inlet 26 and the outlet lines 24, the proportion of materialto gas being maintained constant in order to ensure uniform abradingaction. With uniform abrading action it is possible to control theextent of abrasion efiected on a given workpiece by precisely timing theexposure of the workpiece to the stream.

-In order to provide the high velocity stream as aforesaid, an aircompressor (not shown) may serve as a source of air pressurized in theorder of between 225 and 250 p.s.i. for delivery to the vessel 10. Gasesother than air may also be employed in carrying out the invention. Inaddition, low pressures such as p.s.i. may be employed for carryingalumina particles with approximately the same cutting effect as glassbead particles carried by air at 225 p.s.i. Thus, air pressure may bevaried in relation to the desired cutting action; and it is conveyedfrom the source by an inlet supply pipe 28 connected by a fitting 30 toa threaded portion of the inlet 26 in base 12. A baffle 32 serves todisperse the incoming air and thus prevent scattering of abrasiveparticles onto moving mechanical parts. A suitable heater 34, of theelectrical type for example, may be installed on the pipe 28 to preheatthe pressurized air to about F. in the interest of lowering its relativehumidity. Flow through the inlet supply pipe may be controlled by amanually operable valve 35.

The shell 14 is secured to the base 12 in fluid tight relationship bymeans of a rotary bayonet lock comprising irrterlocking inner and outerrings 36 and 38 secured respectively to the rim of the shell and to theupper surface of the base. The rings 36 and 38 have sinuate marginsoverlapping one another in opposite radial directions whereby the crests40 of the inner ring 36 will register with the depressions 42 in theouter ring 38 in the unlocked position of these parts but otherwise thecrests 44 of the outer ring will register with and overlap the crests 40of the inner ring 36, as in the locked position shown in FIG. 2.

In order to limit relative rotational movement of the rings 36 and 38when locking the assembly, a pair of stop pins 46 are spaced 180 apartin the arrangement, as best seen in FIG. 2, to provide an abutment inthe path of portions of the inner ring 36. Opening movement involvescounterclockwise movement of the inner ring 36 and shell 14, as viewedin FIG. 2.

A handle 48 is secured to the inner ring 36 to facilitate rotationalmovement of the inner ring and shell assembly relative to the outer ring38 and base 12 assembly, as during locking and unlocking of theseassemblies to one another.

When the vessel assembly is locked as aforesaid an electromagneticallyoperable dump valve 50 in inlet supply pipe 28 is held closed to theatmosphere by energization from electric current flowing through aclosed microswitch 52 mounted on the outer ring 38 and arranged to beheld closed through engagement of its plunger by a finger 54 mounted onthe inner ring 36, as shown in both views. In unlocked position of thevessel parts the finger 54 will disengage the plunger of microswitch 52and deenergization of the dump valve 50 opens the inlet supply pipe 28to atmosphere, thus preventing pressurization of the vessel when theshell 14 is not sealed to the base 12.

There will now be described a device for signalling, or actuatinganother component, when the supply of abrasive powder in the reservoir18 is reduced to a predetermined level or depleted. The stand 20 iscomprised of upright tubular legs 56, preferably four in number, whichare braced by upper and lower rings 58 and 60. The upper ends of thelegs 56 are arranged to support the trunco conically shaped lower wall62, below the annular outer wall 63 of the reservoir 18, throughupwardly biased plungers 64. Each plunger 64 is slidably received in anupper portion of its associated leg 56 and biased upwardly by acompression spring 66 compressed against a [firmly held plug 68 or otherform of abutment surface. The springs 66 are selected to have suitableresilience or spring constant to elevate the reservoir 18 as the supplyof abrasive material in the reservoir is reduced, thereby releasing theupwardly biased switch handle 70 of a normally closed switch 72 to closethe electrical circuit through a warning lamp 14 when the reservoir 18is nearly empty. Obviously, the means responsive to upward movement ofthe reservoir just described may be employed for actuating ordeactuating electrically responsive devices other than lamp 74, or inaddition to lamp 74, if so desired.

The distributor 22 for abrasive material is disposed within the pressurevessel and comprises a bowl 76, or other suitable container preferablyopen at the top, and mounted for angular movement about an upright axison a driving mechanism 78. The bowl 76 may be secured to the drivingmechanism 78 by a bolt or other suitable means. The bowl 76 is providedwith outlet means in the form of tubes 80 disposed horizontally andtangent to the annular bowl wall. The bottom wall '82 of the bowl 76 isdownwardly sloping as it extends outwardly of center, thus directing theflow of abrasive material toward the outlet tubes 80. The outer ends ofthe tubes 80 are positioned above the respective mouths of the funnelentrances 23 to the outlet lines 24.

With the foregoing arrangement of the outlet tubes 80 and the funnelentrances 23 of lines 24 it should now be apparent that it isadvantageous to limit the angular motion of the bowl 76 by the drivingmechanism 78. Preferably, in this regard, the extent of arcuate movementof the outer ends of the tubes is no greater than the are distance alongthe path of such movement across the top of the funnel entrance 23. Thisprovision minimizes spillage of abrasive material and effectivelydelivers a free flowing supply of such material into the mouths of thelines 24, while at the same time admitting air or gas for flowtherethrough as a carrier stream.

The driving mechanism 78 is suitably a so-called Syntron rotary vibratorwhich reciprocates the bowl 76 in an inclined arcuate path about theaxis of movement. Thus driven, the bowl 76 is lifted and turned in onedirection of movement, so as to increase the normal force between thebottom wall 82 and the abrasive material. Abrasive material is therebydispatched in a tangential path through the tubes 80. On the return orreverse stroke the bowl '76 is oppositely driven by the mechanism 78 tothe same limited arcuate extent back to original position, but thisdeclining arcuate path of movement is with reduced normal force andtherefore with little or no driving effect on abrasive particles.

Optionally, the passageway, within each outlet tube may be kept clear,that is, free of accumulated abrasive material, by installing a loosewire member 84 therein which vibrates in response to motion of thedistributor 22. Only one such wire 84 is shown in FIG. 2 for the sake ofclarity, but each tube 80 can be so equipped if desired. The diameter ofthe wire member 84 can also be selectively adjusted to produce thedesired amount of flow through its associated tube 80. Obviously, theflow area through a given tube 80 is reduced with a larger wire member84 and vice versa. This feature can likewise be employed to adjust therelative flow rates of the abrasive streams leaving bowl 76. Moreover,by keeping the tubes 80 clear there is instant starting of the abrasivestreams after shut down of the apparatus. By bending the ends of member84 it will be held in position during operation, as illustrated.

During start-up it may be desired to introduce air to the pressurevessel at a slow rate until the desired pressure is reached. Suitably,this can be accomplished by providing a restricted conduit 86, forexample A diameter conduit as compared with 1" diameter conduit forinlet pipe 28, to bypass the valve 35; and a flow valve 88 as furtherrequired to control flow through the bypass con- What is claimed is:

1. Abrading apparatus comprising:

nozzle means,

a source of pressurized gas,

a pressure vessel including a base and wall structure defining a shell,

a storage reservoir for abrasive material disposed within said vessel,

means for supporting said reservoir,

a distributor for abrasive material disposed within said vessel andcomprising a container for abrasive material, said container beingmounted for angular movement about an upright axis and being providedwith outlet means at spaced locations about said axis,

means for conveying abrasive material from said storage reservoir tosaid container for replenishing the supply of abrasive material therein,

means for driving said distributor angularly about said axis todischarge abrasive material from said container through said outletmeans,

first conduit means connected between said pressurized gas source andsaid vessel for delivering gas to said vessel and pressurizing theinterior thereof,

and second conduit means connected between said nozzle means and saidvessel and having inlet means for the respective outlet means of saiddistributor arranged adjacent thereto for receiving abrasive materialfrom said distributor and gas from said vessel and for conveyinggas-borne abrasive material to said nozzle means.

2. Abrading apparatus according to claim 1 wherein said container is abowl with annular wall structure formed about said axis, and said outletmeans comprises at least one tubular member extending generallytangentially to said annular wall structure.

3. Abrading apparatus according to claim 1 wherein said driving meanscomprises a rotary vibrator, a driving member connecting said containerto said vibrator, and means guiding said driving member for movement inan inclined arcuate path about said upright axis, whereby said containerreceives reciprocating drive impulses which lifts and throws saidabrasive material out said outlet means in one direction of arcuatemovement and returns to original position after arcuate movement inopposite direction.

4. Abrading apparatus according to claim 1 wherein the supporting meansfor said reservoir includes resilient structure biasing said reservoirupwardly against the weight of abrasive material stored therein, andfurther including means responsive to upward movement of said reservoirto a predetermined position as the supply of abrasive material is beingdepleted for signalling such condition.

5. Apparatus according to claim 1 wherein said base and said wallstructure are separable to provide access to the interior of saidvessel, and further including sealing means and a rotary lock betweensaid base and the bottom of said wall structure, and switch meansresponsive to movement of said wall structure to locked and unlockedpositions relative to said base for signalling when said Wall structureis not locked to said base.

6. Abrading apparatus according to claim 5 further including a normallyopen valve in said first conduit means responsive to signalling by saidswitch means for closing said first conduit means when said wallstructure is not locked to said base.

7. Apparatus according to claim 1 wherein said container includesannular wall structure formed about said axis, said outlet meanscomprises a plurality of tubular members extending generallyhorizontally and generally tangentially to said annular wall structure,said driving means includes a rotary vibrator for reciprocating saidcontainer in an inclined arcuate path about said axis, and therespective inlet means of said second conduit means define openingspositioned below the outer ends of said tubular members to receiveabrasive material discharged therefrom for mixture with pressurized gasand conveyance thereby to the respective nozzle means.

8. Abrading apparatus according to claim 2, further including a wireelement loosely disposed in said tubular member and extendingtherethrough to maintain said tubular member free of deposited abrasivematerial by movement therein in response to angular movement of saidcontainer.

9. Abrading apparatus according to claim 7 wherein the extent of arcuatemovement by the outer ends of said tubular members in one direction isno greater than the arc distance along said path across the openingdefined by said inlet means.

10. Abrading apparatus according to claim 1 further includingselectively operable means for heating the gas flowing through saidfirst conduit means.

References Cited UNITED STATES PATENTS 2,696,049 12/1954 Black 51-12 X2,919,517 1/1960 Hestad et al. 51-8 3,344,524 10/ 1967 Kulischenko 51l2X LESTER M. SWINGLE, Primary Examiner

